Electric heaters for railway permanent way systems



, p 1964 A. COATES ETAL ELECTRIC HEATERS FOR RAIL-WAY PERMANENT WAYSYSTEMS Fileci' Oct. 8, 1962 v 2 Sheets-Sheet 1 INVENTQRS A. Coai'es 6.B. Russ ATTQZNELY p 1, 1964 A. COATES ETAL 3,146,977

ELECTRIC HEATERS FOR RAILWAY PERMANENT WAY SYSTEMS Filed Oct. 8, 1962 2Sheets-Sheet 2 .h I I I E M L' K w 3 2 j 9 INVENTORS Acoates GHRusse/lBY H, Bi-r-cl-nenhough MJZ/JMM United States Patent M ELECTRIC HEATERSFOR RAILWAY PERMA- NENT WAY SYSTEMS Arthur Coates, Leeds, and Gordon B.Russell, Scholes, near Leeds, England, and Herbert Birchenhough, 17Tennison Ave., Borehamwood, Hertfordshire, England; said Coates and saidRussell assignors to Geo Bray & Co. Limited, Leeds, England Filed Oct.8, 1962, Ser. No. 228,984 4 Claims. (Cl. 246-428) This invention relatesto electric heaters for railway permanent way systems, the purpose ofsuch heaters being to prevent ice and snow accumulation in the vicinityof moving parts which may in turn prevent operation of mechanically ormanually operated switch rails.

It is already known to clamp electric heaters or electrically heated oilpipe circuits to a rail of a permanent way, but the mechanical clampingmeans used have involved structural modification to the rail on site. Itis accordingly more usual to apply salt or grease by hand to those partsat which freezing is to be avoided but considerable labouris involved inthe adoption of this method and in addition it is found that undesirablecorrosion of the metal parts results from the use of salt.

The object of the present invention is to provide an improved form ofheater eliminating completely any reduction in mechanical strength ofthe parts to be heated and at the same time effectively preventingexcessive ice and snow build up on the points or other movable parts andthereby to reduce the possibility of accidents or traffic delays whichmay otherwise result from inoperation of railway points. The method ofuse affords simplicity of installation normally without disturbanceeither mechanical or physical to the surroundingrail point parts.

According to the present invention an electric heating assembly isconstructed for attachment to a slide chair of a railway permanent wayin situ, the assembly including a heater element the disposition ofwhich is such that heat is transmitted by both conduction and radiationto the slide chair and parts mounted thereon.

In a particular form of heating assembly according to the invention, asheathed wire tubular electric heating element of generally hairpin formcarries near the end of each limb clamping means constructed to engage arail or other member to be heated and the extremities of the heatingelement each terminates in a watertight terminal box.

One form of heater assembly embodying the invention and constructed andarranged to be mounted on a railway slide chair will now be described ingreater detail by'way of example with reference to the accompanyingdrawings in which:

FIGURE 1 is a side elevation of such an assembly mounted on a slidechair, some details being shown in section;

FIGURE 2 is a plan view;

FIGURE 3 is an end elevation as seen from the left of FIGURE 1;

FIGURE 4 is a front elevation of a component which will be referred toas a fixing claw; and

FIGURE 5 is a cross-sectional view taken on the line A--A in FIGURE 2 toan enlarged scale.

Referring to the drawings, a slide chair indicated generally at 1 towhich the heater assembly is applied is of conventional form consistingof a heavy rectangular base plate 2 with holes 3 at the corners for thereception of bolts, not shown, which secure the slide to a sleeper, notshown. The slide is located on the sleeper so that a fixed stock rail 4crosses it transversely near one end, the top horizontal surface 5 ofthe plate providing the slide area for a switched rail, not shown. Theslide M 3,146,977 Patented Sept. 1, 1964 area is raised with respect tothe base plate and is defined by a shoulder 6 which, at the end remotefrom the fixed stock rail is semi-circular in form.

The heating element 7 is of the sheathed wire tubular type of circularcross-section approximately 1 of an inch in diameter and containing acentrally embedded resistor in a refractory insulating cement. Thesheathing is of heat resisting material, is completely impervious tomoisture, and in the particular example being described is formed withdiametrically opposite longitudinal ribs 8 (FIGURES 2 and 5). Anappropriate length of such element is bent into broad generally hairpinformation and the bent end is laid around the vicinity of thesemicircular portion of the shoulder 6 defining the slide area of theslide chair. The limbs of the hairpin extend along each side of theshoulder in close contact therewith up to a point at which each limbbecomes slightly spaced apart from the slide chair and is held by adistance fin 9.

The two fins 9 serve to maintain the heating element in position belowthe horizontal working surface of the slide chair and as will be seenfrom FIGURE 5 each fin is in the form of a bar with a longitudinallyrecessed edge made large enough to accommodate the element. Between thepoints at which the element loses contact with the shoulder 6 of theslide chair and the point of entry 'into the recessed fins, the elementis twisted through 45 about its longitudinal axis so that the ribs 8will be positioned as shown in FIGURE 5. A portion 8a of a rib in thetwisted position is shown in FIGURE 2. Preferably the limbs of theelement are secured in their respective fin recesses by a silver solderor other means of jointing.

The end of each limb passes freely through a hollow bolt 10 whichcarries a claw like clamp 11, the claw portion of which is shaped toengage the lower outer flange 12 of the fixed stock rail 4. Theextremity 13 of each limb of the element then freely passes into a metalterminal box 14 to which the sheath of the element is brazed as at 15 toform a watertight connection. Each terminal box is cylindrical in formand is made completely moisture proof utilising an oil and moisturetight sealing ring 16 and an insulating lining sleeve 17 which surroundsthe connection between the core cable of the heating. element and theend of a supply conductor, not shown. The supply conductor passesthrough a cap 18 on a screw threaded extension 19 of a closure 20 forthe terminal box 14 and a flange 21 of the closure 20 serves to clampthe sealing ring 16.

The head 22 of the sleeve bolt 10 abuts the end of the terminal box 14and a nut 23 on the sleeve abuts the claw clamp 11. Thus, when thesleeve bolt head and the nut are tightened in opposition, the element isclamped in contact with the slide chair and the claw clamp firmly gripsthe stock rail 4 so holding the assembly securely in position. A lockingnut 24 is provided.

In an alternative construction, in order to ensure that the bent end ofthe element shall not lift away from the slide chair, a strip clamp maybe used to hold it down. Thus one end of a horizontally disposedZ-shaped metal strip may be bent over and brazed to the element and theother end secured by a screw bolt to a sleeper.

Although reference has been made to the use of an element havinglongitudinal ribs, it will be understood that any appropriate form ofheating element may alternatively be used and changes in detailedconstruction may be made.

It will be seen that the heating assembly described lends itself toattachment to a slide chair of a railway permanent way in situ withoutrequiring alteration to or modification, disturbance or reduction inmechanical strength of the slide chair or permanent Way.

We claim:

1. An electric heating assembly constructed for attachment to the slidechair of a railway permanent Way in situ, said heating assemblycomprising a heating element of the sheathed wire tubular type andof'hairpin form, clamping means forclarnping-said heating element inheat conductive relation with said slide chair and a fixed track rail onsaid slide chair, the assembly farther comprising a watertight terminalbox for the extremity of each limb of said heating element, saidclamping means consisting of a-pair of clamp members disposed one oneach limb'of said heating element and engaging said fixed track rail,each of said clamp members being in the form of atclaw the jaws of whichengageithe flange of said fixed track rail, a pair of hollow bolts eachof which has one of said claws slidably mounted thereon, said bolts eachhaving a screw-threaded shank and a head and through each of which onelimb of said heating element passes, the head of each bolt beingdisposed in abutting relation-with the terminal box forisaid one limb ofsaid heating-element and each bolt. having thereon a nut which providesan abutment for the claw "slidably mounted thereon.

2. An electric heating assembly according to claim 1 in whichrneans areprovided for retaining the heating element below the level of thehorizontalslide face of said slide chair.

'3. An electric heating assembly constructed for attachment to the slidechair of a railway permanent way in situ, said heating assemblycomprising a length of heating element of the sheathed wire tubular typebent to conform with the shape of a portion of the slide chair, clampingmeans for clamping said heating element in heat conductive relation withsaid slide chair and a fixed track rail on said slide chair, theassembly further comprising a watertight terminal box for the extremityof each limb of said heating element, said clamping means consisting ofa pair of clamp members disposed one on each limb of said heatingelement and engaging said fixed track rail, each of said clamp membersbeing in the form of a claw the jaws of which engage the flange of saidfixed track rail, a pair of hollow bolts each of which has one 1References Cited inthe file of this patent UNITED STATES. PATENTS1,329,007 Paige Jan. 27, 1920 1,474,161 Packer Nov. 13, 1923 1,897,218Scholz- Feb. 14, 1933 1,957,977 Packer May 8, 1934

1. AN ELECTRIC HEATING ASSEMBLY CONSTRUCTED FOR ATTACHMENT TO THE SLIDECHAIR OF A RAILWAY PERMANENT WAY IN SITU, SAID HEATING ASSEMBLYCOMPRISING A HEATING ELEMENT OF THE SHEATHED WIRE TUBULAR TYPE AND OFHAIRPIN FORM, CLAMPING MEANS FOR CLAMPING SAID HEATING ELEMENT IN HEATCONDUCTIVE RELATION WITH SAID SLIDE CHAIR AND A FIXED TRACK RAIL ON SAIDSLIDE CHAIR, THE ASSEMBLY FURTHER COMPRISING A WATERTIGHT TERMINAL BOXFOR THE EXTREMITY OF EACH LIMB OF SAID HEATING ELEMENT, SAID CLAMPINGMEANS CONSISTING OF A PAIR OF CLAMP MEMBERS DISPOSED ONE ON EACH LIMB OFSAID HEATING ELEMENT AND ENGAGING SAID FIXED TRACK RAIL, EACH OF SAIDCLAMP MEMBERS BEING IN THE FORM